He was killed along with Pat Tait, pictured, three weeks later as they sat in a Land Rover in the Essex village of Rettendon

And a secret recording made by Met Police during a cop corruption investigation allegedly saw one crime boss pledge to "take out" the suppliers.

Neither the crime boss nor the police officer allegedly involved in the conversation can be named for legal reasons.

An extract from a secret 2002 Scotland Yard report, seen by The Sunday Mirror, read: "On 16th November 1995 [ex-officer named]… met [crime lord named] who offered the hand of friendship, by offering to take out the supplier of the drugs to Leah Betts, who died of an ­overdose.”

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The two men jailed for the 1995 Rettendon murders remain behind bars after their conviction in 1998.

Michael Steele, 74, and Jack Whomes, 55, are expected to use the allegations in their bid for freedom over the conviction they have always denied.

Gangsters Pat Tait, 37, Tony Tucker, 38, and Craig Rolfe, 26, were shot dead inside their Land Rover in a rural spot near the Essex village Rettendon.

The killing went on to become one of the most notorious in British crime history and sparked a number of films including Essex Boys - starring Sean Bean.